Voltage-activated and stretch-activated Ba2+ conducting channels in an osteoblast-like cell line (UMR 106).

Calcium entry may mediate osteoblast activation by calciotropic hormones or changes in electrical fields or mechanical stress in bone. Using cell-attached patch clamping techniques, we have seen two Ba2+ conducting channels in UMR-106 osteoblast-like cells: (i) a voltage-dependent, dihydropyridine-sensitive channel resembling L-type Ca2+ channels in other cells, and (ii) a stretch-activated non-selective channel resembling those involved in mechanoreception and triggering of volume regulation in other cells.